PROJECT SUMMARY/ABSTRACT Poor diet quality contributes to the excess burden of cardiometabolic diseases among U.S. adults. Short sleep and poor quality sleep are increasing and have been linked to obesity and cardiometabolic diseases. There is evidence that both diet and reduced sleep duration and quality impact African Americans and those with low socio-economic status more so than other groups, and that these differences may contribute to health disparities in cardiometabolic diseases. Specific aspects of diet have been linked to sleep outcomes in the short term and similarly, experimental studies of sleep restriction have found short sleep can lead to poor dietary choices and weight gain, demonstrating the bi-directionality of the diet and sleep relationship in the near term. However, the inter-relationship between diet and sleep is complex and has rarely been studied in the long-term nor with aspects of sleep beyond duration including quality, regularity, disturbance, and sleepiness. Therefor, this study will address this knowledge gap by examining the long-term relationships between diet and sleep in the Bogalusa Heart Study cohort of 1250 men and women from a biracial community in Louisiana that have been prospectively followed for over 40 years, since childhood. The first aim of the research is to prospectively examine the effect of multiple aspects of sleep (e.g. duration, quality, sleepiness) on dietary intake in midlife among the Bogalusa Heart Study cohort. The second aim of the research is to prospectively examine the effect of dietary intake in young adulthood on long-term sleep outcomes later in life including sleep duration, quality, regularity, disturbance, and sleepiness accounting for body mass index, risk for sleep disordered breathing, and physical activity. The third aim is to determine if differences by race, biologic sex, and socioeconomic status exist in the relationships between diet and sleep over the life course. The long-term goal in pursuing this research project and training plan is to produce an independent investigator in nutritional and lifestyle epidemiology, well prepared to pursue a research career that alleviates the burden of disparity in obesity and obesity-related morbidity and mortality for people in the Gulf South Region of the United States. This will be achieved by meeting the overall objective of this project, implementing a tailored, individualized, mentored research training experience that contributes to closing a long-standing knowledge gap in the long-term relationship between diet and sleep. The impact of this work will be to produce a future leader in nutritional and lifestyle epidemiology. The knowledge gained will allow for the development of appropriately timed and targeted intervention opportunities to maintain healthy weight and sleep patterns that prevent chronic cardiometabolic diseases among diverse populations in the U.S. while reducing health disparities. The Bogalusa Heart Study cohort is a unique and ideal setting in which to perform this research.